Currently, we are unable to delete contents that were used by old campaigns due to the fact that you cannot delete old campaigns either. When you attempt to delete a content associated with an old campaign, an error message is displayed. Users are stuck with a bunch of contents in their account and no way to get rid of them even though they really are not in use. The content is no longer affecting any campaigns technically, however since it was used a long time ago for 1 email campaign that also cannot be deleted, we are stuck with it forever.
